1. Field of the Invention
This invention relates generally to an anchoring device for use in rock crevices and the like during rock climbing activities and, more particularly, it relates to an anchoring device for use in rock crevices and the like which utilizes an overlapping dual cam supported on an axle thereby inhibiting any induced moment on the axle while supporting a climber during rock climbing activities.
2. Description of the Prior Art
When two or more climbers move over difficult or dangerous ground, it is highly advisable and common practice to utilize a rope to secure the climbers together and to anchor the rope in slidable manner to the face being climbed. Furthermore, it is prudent to obtain a firm anchor to which the rope can be suitably secured.
In the past, numerous devices have been devised to assist climbers in securing ropes to cracks or crevices in rock walls for the purpose of climbing safety. Such anchors can be natural, i.e. rock spikes, flakes, chockstones jammed in cracks, natural rock threads, and the like. With such anchors, a separate loop of rope or webbing is attached to the natural anchor and to which the climbing rope is slidably secured. As an alternative to natural anchors, artificial anchors can be utilized. Thus, artificial chockstones or nuts are known of a variety of shapes and sizes and which are inserted into cracks or holes in the face being climbed where they can be made to jam. Pitons, also known, are steel spike-like members of various shapes and sizes which can be hammered into cracks or crevices in the rock face. Yet again, it is known to provide bolts, a modified form of piton and which are designed to be hammered into drilled holes in solid rock.
So far as natural anchors are concerned, these have no inherent disadvantage so long as the rock of the face being climbed is firm and not smooth. However, at the start of a climb it is often apparent that there are an insufficient number of natural anchors existing over the whole face. Artificial chockstones provide an efficient anchor especially when placed in an uneven (ragged) crack, but placing the artificial chockstone in place tends to be somewhat difficult and/or time consuming, and even good placements can be dislodged by movement of the climbing rope. When all that is available, where an anchor is needed, is a smooth-sided, parallel-sided crack, placement of the chockstones is difficult both to make and to ensure it is secured.
Both pitons and bolts again provide extremely efficient anchors, but with pitons being made from steel they tend to be heavy and can be difficult to place. Also, removal of pitons can be extremely difficult and as they tend to scar the rock surface, many climbers are unwilling to use them. Similarly, bolts take an appreciable length of time to place and cause a permanent disfiguration of the rock face. Due to these problems, there is an unwillingness among the climbers to employ bolts, except as a last resort.
More recently, spring loaded camming devices are used incorporating multiple pivoting cams which are spring-biased toward an open position to allow placement of these devices securely into rock cracks and rock crevices of varying sizes. To position the camming devices, the climber simply pulls a trigger closing the cams until the cams fit within the rock crack or crevice. The climber then releases the trigger and the spring or springs expand forcing the cams against the rock surface. Once a load is placed on the camming device, the cams expand and secure the climber to the rock face. An induced static friction force between the camming device and the rock face counteracts the applied load. Because such devices can be subject to substantial loads in holding a falling climber, it is desirable to construct such anchors in a manner which provides the greatest possible structural integrity of the device.
Spring loaded camming devices revolutionized climbing by allowing climbers to protect parallel-sided cracks in a variety of sizes. Conventionally shaped pivoting cam devices utilizing offset cams are constructed such that if only two conventionally shaped cams were used, the reaction forces caused by the supported weight of the climber create a moment on the axle connecting the offset cams. If sufficient force is applied, the pivoting cam device will begin rotating and release its hold on the rock. Other pivoting cam devices are too large for many piton scars and rock crevices and are, therefore, either not usable in many situations or cause the climber to use only a portion of the device thereby creating an unstable, and potentially dangerous, situation.
Accordingly, there exists a need for an anchoring device for use in rock crevices and the like which sufficiently supports a climber during rock climbing activities. Additionally, a need exists for a an anchoring device for use in rock crevices and the like which inhibits the creation of an induced moment by the reaction forces from the supported weight of the climber. Furthermore, there exists a need for an anchoring device for use in rock crevices and the like during rock climbing activities which utilizes an overlapping dual cam supported on an axle thereby inhibiting any induced moment on the axle while supporting a climber during rock climbing activities.
The present invention is an anchoring device for use in a rock crevice. The rock crevice is defined by a first rock wall and an opposing second rock wall. The anchoring device comprises an axle member having a longitudinal axis. A first cam is rotatable about the longitudinal axis of the axle member and contactable with the first rock wall with the first cam having a first side wall and a second side wall. A second cam is rotatable about the longitudinal axis of the axle member and contactable with the second rock wall with the second cam having a first side wall and a second side wall. The first side wall of the first cam is aligned with the first side wall of the second cam and the second side wall of the first cam is aligned with the second side wall of the second cam. Upon a first force being applied to the first cam by the first rock wall and a second force being applied to the second cam by the second rock wall in a direction generally toward the longitudinal axis, the axle member is free from any created moment.
The present invention additionally includes an anchoring system for releasably securing a climber to a rock face with the rock face having a rock crevice. The anchoring system comprises an axle member, a first cam member having a first supporting surface and a first contact surface with the first cam member rotatable about the axle member, and a second cam member having a second supporting surface and a second contact surface with the second cam member rotatable about the axle member. Upon a force being applied to the first supporting surface of the first cam member and the first supporting surface of the second cam member in a direction generally toward the axle member, the first cam member contacts the second contact surface of the second cam member and the second cam member contacts the first contact surface of the first cam member.
The present invention further includes a method for securing a climber to a rock face. The method comprises providing a first cam and a second cam, rotatably securing the first cam and the second cam to an axle member, aligning the first cam with the second cam, applying a force to the first cam and the second cam in a general direction toward the axle member, contacting the first cam with the second cam, and inhibiting any created moment on the axle member.